Chemical process and product



Patented Jan. 2, 1945 .1U NlTE-D onnmcsnrnoosss m rnonuc'r Frederick W. Breuer, Havel-lord, 1's... alsi nor to The United Gas Improvement Company, a cor poration of Pennsylvania No Drawing. Application June 25,1942 seflll N0. 448,435

7' Claims. (Cl. 260-680) This inventionpertainsigenerally to the preparation oi'unsaturated hydrocarbons and pertains particularly to the preparation of unsaturated hydrocarbons oi the allenic type.

It has been known to the prior art "(Paul and Hilly, Comptes R'endus 208,608, 1930; and. Bull.

- S00. Chim. 8',.218, 1939) that'the tnple'bond between 2 carbon atoms can be reduced tosthe double linkage, if catalytic iron; Prepared-from aluminum iron alloys preferably of 10 to only. and is immediately'transierred to e nonaqueous dispersingaaent, such as' -ethyialcohol. The catalyst and -monovinyl acetylene are placed with or withoutthe addition ofpoiymerby weight 01' iron content, bysthe' method or dissolving the bulk oialuminum' selectively, is applied as hydrogenation catalyst.

It has now been discovered that in-the" hydroeenation oi oleiinacetylenes of'the'type v RIRMHECRG over said iron catalyst 1:2: dioleflnes instead of 1,3 dioieiines are formed. This mode of hydrogen addition could not have been predicted on the basis oi the known art.

The formation of 1,2- dioleflns from said types oi olefin acetylenes is best explained by the mechanism 011.4 addition, the resulting compounds being of the allenlc type.

The reaction may be represented by the foliowins equation:

ization inhibitor in a suitable pressure" hydrogenation apparatus. -Hydrogenation ir carrie'd out at elevated temperatures and pressures, temperature ranges of to C. and pressures 01' 400 to 800- pounds per sq. in. being Motherly suited for the process. The'hydrogenation reaction isbest when the calculated quantity of hydrogen has been -absorbed'."-- :Followins customary technique ior the isolation of the prodnot a satisfactory yield of butadienelz (methyl allene) is obtained. This hydrooarbon'boils at 10 C. iii-accordance with the-literature data and is further identified by its tetra bromide.

' sample 2 Iron catalyst is prepared from 46. g. of powdered iron aluminum alloy of the composition oi 10% Fe and 90% Al by weight. Thls' ailoy is added slowly and with stirring to a solution of each of m. in. a. and a. mummiehydroseu or an organic radical, for example, an alkyl radi- In the case oimonovinyl acetylene the-equestion Fe CHg-CH-JZHECE WH-O-CH:

represents the reaction.

Regardless of thecorrectness' ot'the'above hypothesis ailenici types.'previously obtainable only through a series of winvoived reactionsahave; be-

- come readily. available bythe: above; described invention.

/ The iollowineexamples'will eervetoziurther nhistrate theinv'ention.

. trample l p I Iron catalyst is prepared by iron aluminum slloyoi preferably 10 to 30% Wt '01 iron content inv essentiallyihefisarnewas: as in the well "known, preparation or Bar ey. .niekel catalyst. Because oi the high degree ot'reectivity with water the-active iron islefreincontaot with aqueous solvents ior a or-- time 184 g. of sodium hydroxide in 200 cc. of boiled out water, the temperature of the mixture not being permitted to rise above 90" C.- The addition oi. the alloy required 2% hours. The mixtureis placed on a water bath for one hour and after decantinc a solution of 184 8- 01' sodium hydroxide in 200 cc. 0! boiled out water is main added to complete the dissolution of the bulk oi the aluminum. After a period of concentration of one and one half hours the black iron powder is permitted to settle and the supernatant solution isdecented. The iron precipitate is washed three times with boiled out water, transferred to a fliter=and washed with boiled out water until the washings are neutral towards phenolphthalein. The active iron is then washed wlth'swt ethyl alcohol and iinally washed with. absolute alcohol. It is suspended. in '10 cc. oifabsolute ethyl alcohol.

' oorreepondineinci'easein'hydrogenpressure'ircm 23". C. to approidmately 0. er a period of with ately 'lhoura' Freshly distilled monovinyl acetylene (2d 8.= 0.5 mole), and the iron catalyst-'p tl redaccording to the: description-presented above, are

placed in a-suitably' cooled pressure yessel quipped for shaking and heatin and are-subiected to a hydroeen (cause) measured at 23' C. and heated with m'. 4 r y 'I'he-tempera'tureisgradually The unabsorbed bydroscn is then released, care pressure 01-560 lbs/sq. in.-

being taken to collect in a dryice cooled trap any volatile reaction products. The hydrogenation bomb is cooled to approximately 50 C. and its contents recovered completely by washing twice with each 25 cc. 95% ethyl alcohol. The iron catalyst is separated from the solution of the reaction products by filtration. The solution (112 cc.) contains unreacted monovinyl acetylene as evidenced by a test .with silver nitrate.

Upon iractionating through a i'ractionating column of an efllciency equivalent to say 13' theoretical plates a fraction of butadiene 1,2 (4.14 g.) boiling between 8 to 10 C. at atmospheric pressure. is obtained.

It will be understood that the foregoing is by way of illustration.

Examples of polymerization inhibitors for use for example, as in Example 1, are as follows:

wherein each of R1, R2, R3, and R4 is one of a group consisting of hydrogen and an alkyl radical comprising hydrogenating in the presence of an activated iron catalyst a compound of the formula - RIRZC=CRSVCECR4 wherein each of R1, Ra, R: and R4 has the same meaning as before.

2. A process for the manufacture of butadiene- 1,2 comprising hydrogenating monovinyl acetylene in the presence of an activated iron catalyst prepared by dissolving the bulk oi aluminum from an iron aluminum alloy.

3. A process for producing a compound oi. the formula CHs-CH=C=CH2 comprising subjecting a compound of theiiormula cm=cn-c=cn to hydrogenation conditions in the presence of an activated iron catalyst. 4. A process for preparing butadiene-1,2 comprising hydrogenating monovinyl acetylene in the presence of an activated iron catalyst prepared by dissolving the bulk of aluminum from an iron aluminum alloy, said hydrogenation being carried out at elevated temperatures and pressures in the presence or a polymerization inhibitor.

5. A process for the manufacture of butadiene- L2 comprising hydrogenating monovinyl acetylene in the presence of an activated iron catalyst obtainable by dissolving the bulk of aluminum from an iron aluminum alloy, said hydrogenation being carried out at elevated pressures.

6. A process for the manufacture of butadiene- 1,2 comprising hydrogenating, at elevated pressures and temperatures, monovinyl acetylene in the presence of an activated iron catalyst obtainable by dissolving the bulk of aluminum from an iron aluminum alloy.

'7. A process for the manufacture of butadiene- 1,2 comprising hydrogenating monovinyl acetylene over an activated iron catalyst obtainable by dissolving the bulk of aluminum from an iron aluminum alloy, said hydrogenation being carried out in the presence of a polymerization inhibitor.

. FREDERICK W. BREUER. 

